Work driving device for automatic camshaft grinding machine

ABSTRACT

A work driving apparatus for a machine tool, such as a cam contour grinding machine, for applying a driving torque against two spaced angular points through end portion (57) and a carbide block (64), to rotate the workpiece with minimal radial displacement. A driving block (41) is hinged to a face plate (28) to enable the driving block (41) to compensate for size variations of the workpiece and to insure concentricity with the periphery of the workpiece (W), such as an automotive camshaft. Rotation of the work driving device (26) automatically angularly orients the workpiece relative, for example, to a master cam (19), as work rest pressure restrains rotation of the workpiece. This allows an automatic work loader to be used without any devices to regulate the angular position of the workpiece.

United States Patent [151 3,667,167

Happel 1 June 6, 1972 54] WORK DRIVING DEVICE FOR 3,585,763 6/1971 Clark..51 237 cs AUTOMATIC CAMSHAFT GRINDING ,6 7 8/1971 MACHINE UNLOAD I00 gf Primary Examiner-Othell M. Simpson Att0rneyDavid S. Urey [5 7]ABSTRACT A work driving apparatus for a machine tool, such as a camcontour grinding machine, for applying a driving torque against twospaced angular points through end portion (57) and a carbide block (64),to rotate the workpiece with minimal radial displacement. A drivingblock (41) is hinged to a face plate (28) to enable the driving block(41) to compensate for size variations of the workpiece and to insureconcentricity with the periphery of the workpiece (W), such as anautomotive camshaft. Rotation of the work driving device (26)automatically angularly orients the workpiece relative, for example, toa master cam (19), as work rest pressure restrains rotation of theworkpiece. This allows an automatic work loader to be used without anydevices to regulate the angular position of the workpiece,

5 Claims, 5 Drawing Figures g/IIIIIIIIIIIIIIIII-Iz, i. ,,,,,,.,..,,,.z..zz"

as I 91 4L8 LOADER ARMS LOADER ARMS whim SOL SOL 87 HYDRAULIC SUPPLY \Las 3 AIR SUPPLY EXHAUST EXHAUST ITS- g mot,

LOADER LOADER v02 UNCLAMP CLAMP Kiku'chi ..51/215 R PATENTEDJuu 6 I972SHEET 10F 2 FIG. I

LOADER ARMS DOWN SOL HYDRAULIC SUPPLY INVENTOR WlLLlAM E. HAPPEL LOADERARMS SOL EXHAUST AIR SUPPLY I LOADER I00 98 CLAMP J LOADER UNCLAMP IOIEXHAUST ATTORNEY PATENTEDJUH 6 I972 3,667. 167

INVENTOR W\LL\AM E. HAPPEL ATTORNEY WORK DRIVING DEVICE FOR AUTOMATICCAMSI'IAFI GRINDING MACHINE BACKGROUND OF THE INVENTION 1. Field of theInvention This invention relates to new and useful improvements in workdriving devices for driving workpieces for a machining operation, andmore particularly, a work driving device for use on an automaticcamshaft grinder for driving a camshaft during the grinding of camcontours thereof.

The work driving device is particularly adapted for use in orienting anddriving a workpiece, such as a camshaft having an extended portion orkey which is substantially used for securing a cam gear or sprocket tothe camshaft.

This invention has particular application on automatic cam contourgrinders and enables an automatic loader to be used. The loader placesthe workpieces on the conventional work rests in any random angularorientation. Friction from the jaw shoes of the work rests is used torestrain rotation of the camshaft while the work driving device isrotated at a slow speed to orient the cam contours relative to theheadstock spindle and the master cam. Driving pressure is obtainedthrough a floating, hingedly mounted work driver which transmits asubstantially pure driving torque to rotate the workpiece.

The work driving device may be used to drive any cylindrical workpiecefrom a positive angular position automatically which enables anautomatic work loader to be used.

2. Description of the Prior Art Prior to this invention, the means fordriving a camshaft consisted of a removable fixture which was placed oneach camshaft before placing it in a cam grinding machine. This fixturewas removed from the camshaft after the grinding operation. The fixturecooperated with a driving dog on a face plate of a cam grindingapparatus to rotate the camshaft. In this type of arrangement, theapplication of the driving force to rotate the camshaft applied a radialforce which had a tendency to cause radial displacement of the camshaft.

In more recent applications, such as U.S. Ser. No. 744,349, now U.S.Pat. No. 3,585,763 granted June 22, 1971 and U.S. Ser. No. 744,350, nowU.S. Pat. No. 3,579,914, granted May 25, 1971 a work driving device wasformed as part of a camshaft grinding apparatus. This enabled a camshaftto be engaged manually in an oriented relation and driven in a mannerwherein the problem of radial displacement was eliminated by applying adriving torque at two angularly spaced points on a workpiece when theheadstock spindle rotates a floating work driver. The camshaft in eachof these inventions includes a radially offset orienting hole or akeyway, which allows an indexing element to rotate the camshaft in aprecise oriented position relative to the master cam. This method issatisfactory for manual machines, but would not enable an automatic workloader to be used, because the camshaft has to be engaged in an orientedrelationship manually.

SUMMARY OF THE INVENTION In accordance with the invention, the workdriver is used to rotate a workpiece in a machine tool, such as acamshaft in a cam grinder. The workpiece is prowded with a locating anddriving projection, such as a key. The machine includes conventionalmeans for rotating and supporting the workpiece between work centerswhile the workpiece is supported on work rests. The work driver includesa floating driving block having opposed work engaging surfaces. Theblock is hingedly or floatingly mounted so that the work engagingsurfaces can adjust to variances in the periphery of the workpiece. Theblock also includes indexing means which initially will receive theworkpiece in any angular position and subsequently will locate theworkpiece projection or key in a single angular position with respect tothe rotating means. The indexing means forms one driving surface againstthe key and one of the work engaging surfaces forms another to apply amechanical couple, which is substantially free of forces which tend toshift the workpiece radially relative to the work centers. Theworkpieces may be automatically loaded onto the work rests in randomangular positions. One of the work centers is advanced to move theworkpiece into the work driver and against the other work center. Thework rests restrain the rotation of the workpiece while the work driveris slowly rotated to locate the key in the indexing means, whereafter amachining operation is performed.

In the preferred embodiment, the indexing means includes a pair ofpivotally mounted, opposed fingers which are spaced to engage oppositesides of the key. The fingers are resiliently urged into the engagingposition, but they can pivot away therefrom when the workpiece isinitially advanced into the work driving device if the key strikeseither of the fingers.

It is, therefore, an object of the present invention to provide a workdriving device which enables a workpiece to be received in a randomangular orientation, and thereafter be oriented in the deviceautomatically to one specific angular position.

A further object of this invention is to provide a work driving devicewhich applies nearly pure torque or turning forces to the workpiece withminimal radial forces, that is, minimal forces which tend to move theworkpiece radially relative to the work centers.

Another object of this invention is to provide a novel work drivingdevice for a camshaft grinding apparatus wherein means are provided toload the camshaft in a random angular relationship to the driver and torotate the headstock spindle at a slow rate, while restraining theworkpiece, until the workpiece is angularly oriented.

Another object of this invention is to control rotation of the camshaftin a manner which will enable the cam lobe contours to be followed bythe grinding wheel with a constant driving pressure from the workdriver, without any backlash or overdriving when the trailing side ofthe cam lobe passes the grinding wheel.

Another object of this invention is to provide a novel work drivingdevice for a camshaft grinding apparatus wherein the work driving deviceutilizes a protruding key from a conventional keyway in the camshaftboth for the automatic orienting of the camshaft and the drivingthereof.

Another object of this invention is to provide a novel work drivingdevice which includes a driving block which is free to float radially toa central position a limited amount to compensate for size variations ofthe workpieces, and to ensure concentricity between the driving blockand the periphery of the workpiece.

With the above and other objects in view that will hereinafter appear,the nature of the invention will be more clearly understood by referenceto the following detailed description, the appended claims and theseveral views illustrated in the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a plan view of a camshaftgrinding apparatus in which the work driving device is utilized;

FIG. 2 is an enlarged fragmentary transverse sectional view taken alongthe line 2-2 of FIG. 1, and shows the work driving device in elevation;

FIG. 3 is a fragmentary axial sectional view taken along the line 33 ofFIG. 3;

FIG. 4 is a fragmentary axial sectional view taken along the line 4-4 ofFIG. 2; and

FIG. 5 is a partial side elevation view of the grinding machine andshows a typical swinging arm-type loader, and the schematic hydrauliccontrols which allow workpieces to be automatically loaded into themachine.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to the drawingsin detail, there are illustrated in FIG. 1, the basic components of aconventional camshaft grinder, which is generally referred to by thenumeral 10. The invention has application to other machine tools, butwill be described herein, by way of example, as it is used on a camshaftgrinder.

The camshaft grinder includes a base 11 on which there is-mounted acradle 12 for imparting a rocking movement to the workpiece W. Atopposite ends of the cradle 12, there are mounted a headstock 13 and atailstock 14. The headstock 13 includes a work center 15, and thetailstock 14 includes a work center 16. A camshaft or other workpiece Wto be ground is mounted for rotation-on the work centers 15 and 16 on alongitudinal axis determined by the work centers.

The headstock 13 also includes a spindle 17, which is driven by means ofa motor 18. The spindle 17 has mountedthereon for rotation therewith amaster cam 19. The master cam 19 is engaged by'a follower 20 to effectrocking of the cradle 12 in timed relation to'the rotation of theworkpiece W so as to produce the desired cam contour thereon. Thecamshaft grinder 10 includes a grinding wheel 21 which is mounted in aconventional manner for selected engagement with the lobes of thecamshaft or workpiece W.

Reference is now made to FIGS. 2 and 3 in particular, wherein there isillustrated aworkpiece W to be ground. The illustrated workpiece W is acamshaft of which only a front portion thereof is illustrated. Thecamshaft has an end portion 22 of a diameter smaller than the heeldiameter of the cam lobes. When the camshaft is finally completed andread for assembly into a motor, the end portion 22 normally haspositioned thereon a cam gear or sprocket (not shown) for driving thecamshaft. In order to couple such a cam gear or sprocket to the camshaftin an oriented relation,.the end portion 22 is provided with a keyway 23in which an indexing element or key 24 of the conventional type willnormally be seated. It is this key 24 which is utilized in the orientingand driving of the camshaft or workpiece W. I

In order to couple the camshaft or workpiece W to a conventional camgrinding apparatus in an oriented relation with respect to the mastercam thereof and for rotation therewith, the camshaft grinder 10 (FIG. 1)is provided with a work driving device 26 which is best shown in FIG. 2.Referring now to 17 in a generally concentric relationship with respectto the work center v15. The work driving device 26 includes an adapter27 which is secured to the-spindle 17 for rotation therewith and in apredetermined oriented relationship with respect to the master cam 19.The adapter 27 has secured thereto a driver head or face plate 28 bymeans of a pair of circumferentially spaced screws 29-29. It is to benoted that the screws 29-29 pass through slotted openings 31-31 in theface plate 28, so that a minor adjustment in a circumferential directionmay be obtained between the face plate 28 and the adapter 27. 7

Referring now to FIGS. 2 and 3 in particular, it will be seen that theadjustment of the face plate 28 relative to the adapter 27 isaccomplished by providing the adapter 27 with a forwardly extending pin32 which projects into a recess 33 formed in the rear side of the faceplate 28. The face plate 28 is machined to carry opposed positioning oradjusting screws 3636 on opposite sides of the recess 33. The screws3636 engage the opposite sides of the pin 32 and are adjustable to varythe angular position of the face plate 28, when the screws 29-29 arelessened.

The faceplate 28 is provided with a central opening 38 through which thework center 15 projects. A driving block or floating member 41 isconnected to the face plate 28 for rotation therewith and for effectingrotation of an associated workpiece W. The floating member 41 includes aright-hand (R.H.) anda left-hand (L.H.) link, 42 and 43, respectively,as shown in FIGS. 2, 3, and 4. The R. H. and L.H. links 42 and 43 arepivotally mounted on pivot pins 44 and 45, which are mounted on the faceplate 28in an angular spaced relation and secured by fasteners 46-46.

FIG. 1, the work drivingdevice'26 is mounted on the spindle The ends ofthe R.H. and L. H. links 42 and 43 remote from the pivot pins 44 and 45,are bifurcated and are provided with studs 47 and 48 respectively, whichare secured thereto. An R.I-I. indexing member or finger 49 is pivotablymounted on the stud 47 and includes a carbide block 51 having a bevelededge 51A on the upper portion to facilitate entrance of the end portion22 of the workpiece W. The carbide block 51 includes an end portion 52which is retained against the R.H. side of the key 24 when a workpiece Wis in the oriented position. An L.H. indexing member -or finger 53 ispivotally mounted about the stud 48 and includes a carbide block 56having a beveled edge 56A on the'upper portion to facilitate entrance ofthe end portion 22.0f the workpiece W. The carbide block 56 includes anend portion 57 which is retained against the L.H. side of the key 24when a workpiece W is in the oriented position. The R.I-I. finger 49 andthe L.H. finger 53 are retained in the closed or work engaging positionby a tension spring 58 which is secured to the lower portion of theR.I-I. and L.H. fingers 49 and 53 respectively, through spring retainers59-59'as shown in FIGS. 3 and 4. It is to be understood that the tensionof the spring 58 is such that it may be readily overcome to permit thecounterclockwise pivoting of the RH. finger 49 or the clockwise pivotingof the L.H. finger 53 as shown by the arrows in FIG. 2. The pivotablemovement of the R.l-l. or L.H. fingers 49 and 53 occurs when the key 24engages one of the carbide blocks 51 or 56 when the camshaft orworkpiece W is being axially shifted into the work driving device 26during the loading operation.

Set screws 60-60 are secured and locked in an extended portion of theR.I-I. and L.H. fingers 49 and 53 to limit the upward movement of theRH. and L.H. fingers 49 and 53.

A support block 61 (FIG. 2), which includes a carbide block 62, issecured to the left-hand surface of the floating member 41 through afastener 63. The carbide block 62 includes a beveled edge 62A, and thethickness of the carbide block 62 is machined to provide a slight amountof deflection when in contact with the workpiece W to retain theworkpiece W against a carbide block 64, which is formed on the righthandsurface of the floating member 41.

A stop block 66 having bifurcated portions 67 and 68 is secured to theouter surface of the face plate 28 at a position which is arcuatelyspaced midway between the pivot pins 44 and 45. A set screw 69 issecured and locked to the portion 67 and carries a compression spring 71to retain a'projection 72 of the floating member 41 against a set screw73 which is secured and locked to the portion 68. The spring 71 urgesthe floating member 41 to the left (FIG. 2) of the loading range, whichenables the workpiece W to contact the carbide block 64 during theloading of the workpiece W. This arrangement will prevent undue strainagainst the spring-loaded carbide block 62 when a workpiece W is loaded.Adjustment of the screws 69 and 73 control the total amount of radialmovement of the floating member 41 to provide a range of movement toallow the work driving device 26 to compensate for size variations ofthe workpiece W, and to insure concentricity between the floating member41 and the periphery of the workpiece W.

A pair of hydraulically operated work rests 75 and 76 (FIGS. 1 and 5)are secured to the rocking work cradle 12 to align the lower work restshoes 78-78 with the main bearing diameters of the workpiece W. Theupper work rest shoes 79-79 are hydraulically advanced to preventrotation of the workpiece W, while the work driving device 26 is rotatedat a slow speed to orient the workpiece W relative to the headstockspindle 17. A typical work rest is disclosed in U.S. application, Ser.No. 839,924, now U.S. Pat. No. 3,591,988, granted July 13, 1971, anddoes not form a part of this invention. This arrangement allows ungroundworkpieces to be loaded by an automatic loader 80 which places theworkpiece ,W on the lower work rest shoes 78-78 by the clockwisemovement of loader arms 81-81 (FIG. 5). This movement is effected aftera clamp member 82 is advanced to provide a holding force between theworkpiece W and the loader arms 81-81 at the start of the loadingoperation. The workpiece W may be loaded in a horizontal positionwithout being concerned with angular position of the key 24. Theworkpiece W is unclamped, and the hydraulic tailstock 14 advances theworkpiece W axially into the work driver 26 and against the headstockcenter 15. The upper work rest shoes 79-79 are then advanced byhydraulic pressure and the workpiece W is restrained against rotation toallow the work driving device 26 to orient the workpiece W relative tothe headstock spindle 17. A carriage 84 is traversed to the right in aconventional manner to align the grinding wheel 21 with the firstportion of the workpiece W to be ground, the grinding wheel 21 will beadvanced in a transverse direction, and the headstock motor 18 willrotate the workpiece W at a high speed for the grinding operation.

OPERATION With particular reference to FIG. 5, it is to be understoodthat the operation of the automatic loader 80 and the work drivingdevice 26 may be operated either automatically or by manual pushbuttoncontrols (not shown).

The workpieces W are automatically loaded into the camshaft grindingmachine by clockwise movement of the loader arms 81 which carry aworkpiece W from a loader magazine 85 to the lower work rest shoes78-78. This movement is effected by the hydraulic system which directs asource of fluid pressure from a line 86 through a control valve 87, to aline 88, when the solenoid lI-IB SOL is energized, which shifts thevalve 87 to the left against spring pressure. Fluid pressure from theline 88 moves a piston rod 89 of a hydraulic motor or cylinder 90 to theleft (FIG. 5). A rack member 9!, which is secured to the piston rod 89,rotates a pinion gear 92 in mesh with the rack member 91.

The pinion gear 92 is secured to a shaft 93 which is rotatably housed ina loader mounting bracket 94 which is secured to the carriage 84.Rotation of the pinion gear 92 rotates the shaft 93 and the loader arms81-81 are lowered in a clockwise direction which places the workpiece Won the work rest shoes 78-78. A clamp arm 95 is also secured to theshaft 93 and is repositioned clockwise by the movement of the rackmember 91.

The loader arms 81-81 are not advanced until the clamp member 82 hasgripped the workpiece W. This occurs when fluid or pneumatic pressure isapplied to advance a piston 96 of a hydraulic motor or cylinder 97,which is secured to the clamp arm 95. This movement is effected by theenergization of the solenoid 3P SOL, which occurs at the start of thecycle after a timed interval which allows a workpiece W to be releasedfrom the loader magazine 85. The energization of the solenoid 3P SOLshifts a valve 98 to the left (FIG. 5). Pneumatic pressure is directedfrom a line 99, through the valve 98 and to the head end of the cylinder97, through a line 100. The piston 96 advances the clamp member 82 toprovide a holding force between the workpiece W and the loader arms81-81 to maintain positive control of the workpiece W during the loadingoperation. A pressure switch 4PS is actuated by pneumatic pressuredirected from a shaft 83, through an opening 83A, when the clamp member82 is completely closed. The actuation of the switch 4PS effectsenergization of the solenoid lI-IP SOL, and the loader arms 81-81 arelowered.

A limit switch 4LS is actuated when the loader arms 81-81 are in thelowered position by contact, for example, with the rack member 91. Theactuation of the limit switch 4LS effects the deenergization of thesolenoid lI-IB SOL, and the control valve 87 is shifted to the right byspring pressure. The actuation of the limit switch 4LS also energizes arelay (not shown) which deenergizes the solenoid 3P SOL, and the valve98 is shifted to the right by spring pressure. The solenoid 4P SOL isenergized, which effects the unclamping of the clamp member 82. Theenergization of the solenoid 4P SOL shifts a control valve 101 to theleft, and pneumatic pressure is directed from the line 99, through thevalve 101, to a line 102. The line 102 directs pneumatic pressure to therod end of the cylinder 97 which retracts the piston 96 and the clampmember 82 releases the workpiece W. A pressure switch SP8 is actuated bypneumatic pressure directed from the shaft 83, through an opening 833when the clamp member 82 is completely opened. The actuation of thepressure switch 3PS effects the energization of a tailstock advancesolenoid (not shown).

The tailstock work center 16 is then advanced by hydraulic pressure tomove the workpiece W axially into the work driving device 26 and againstthe headstock center 15. The upper work rest shoes 79-79 are advanced byhydraulic presure to restrain the workpiece W from rotation. A pressureswitch (not shown) is energized once the upper work rest shoes 79- 79are in the clamping position. The work driving device 26 (FIG. 2) isthen rotated clockwise at a slow speed to orient the workpiece W inrelation to the headstock spindle l7 and the master cam 19. The normaltendency of the workpiece W to rotate by friction between the workcenters 15 and 16 is overcome by the pressure exerted by the work restshoes 78-78 and 79-79.

The headstock motor 18 rotates the spindle l7 and the work drivingdevice 26 at a slow speed. Rotation of the work driving device 26 is ina counterclockwise direction (FIG. 2), and with the workpiece Wrestrained against rotation, the key 24 will normally contact the uppersurface of the carbide block 51 of the RH. finger 49. The R.I-I. finger49 will pivot counterclockwise about the stud 47 as the pressure fromthe tension spring 58 is overcome. The left-hand side of the key 24 willcontact the end portion 57 of the L.H. finger 53 and the R.I-I. finger49 will return to its original position as shown in FIG. 2. Clearancebetween the key 24 and the surfaces end of the portions 52 and 57 issubstantially non-existent when the RH. or L.H. fingers 49 and 53 arereturned to their original position as shown in FIG. 2. In the event thekey 24 engages the carbide block 56 when the workpiece Wis originallyadvanced into the work driving device 26, the above sequence is the sameexcept that the carbide block 56 is initially pivoted in a clockwisedirection prior to rotation of the work driving device 26.

The end portion 22 of the camshaft or workpiece W is in tangentialcontact with the carbide blocks 62 and 64, which aligns the RH. and L.H.links 42 and 43 about the pivot pins 44 and 45. The floating member 41is properly oriented from the periphery of the workpiece W, depending onthe size variance of the end portion 22 of the camshaft or workpiece W.

Rotation of the face plate 28 effects rotation of the work drivingdevice 26 which results in the end portion 57 of the carbide block 56providing a turning force against the key 24 to rotate the workpiece W.The carbide block 64 is in contact with the end portion 22 of thecamshaft or workpiece W to provide true rotation around the axis of thecamshaft or workpiece W, without applying a force which would effectradial displacement.

It is to be understood that the work driving device 26 properly orientsthe workpiece W angularly relative to the master cam 19. Also, becauseof the circumferentially spaced points of driving engagement between theend portion 57 of the carbide block 56 and the carbide block 64 whichacts as a heel against the workpiece W, the force applied to theworkpiece W will be a couple, comprising solely rotational forces. Therewill be substantially no radial force components which would tend toshift the workpiece W radially relative to the work centers 15 and 16. Aplugging switch lPLS is energized during slow rotation of the headstockspindle 17, which effects traverse of the carriage 84 to the right untilthe first cam lobe to be ground is in axial alignment with the grindingwheel 21. The grinding wheel 21 is advanced and the headstock spindle 17is not rotated at high speed in a conventional manner. It should benoted that the lack of clearance between the surfaces 52 and 57 insuresa constant driving pressure from the work driving device 26, without anybacklash or over-driving when the trailing side of the cam lobe passesthe grinding wheel 21.

A driving pin (not shown) secured to the end of the workpiece W could beused to provide means to orient the camshaft in an identical manner. Theclearance between the end portions of the carbide blocks 51 and 56 wouldbe machined to just clear'the diameter of the pin and the key 24 studsby said floating member; would, of course, be omitted. means forresiliently urging said fingers into co-axial align- Although only apreferred embodiment of the work driving ment to engage the key on twosides; and device 26 has been specifically illustrated and described, itis means on said floating member for engaging opposite sides to beunderstood that minor variations may be made in the of the-camshaft toposition the floating member concenwork driving device without departingfrom the spirit of the in- 10 trically with the periphery of thecamshaft, one of said finvention. gers and one of said engaging meansforming spaced force lclaim: applying surfaces to provide a mechanicalcouple to the '1. In a machine tool for removing material from aworkcamshaft, piece, the workpiece having a projecting indexing elementor so that when the camshaft is restrained against rotation and key, themachine including a tool, a headstock and a tailstock said driving headis slowly rotated, the fingers will rotate for rotatably supporting theworkpiece, at least one work rest until the leading finger engages andpivots away from the for supporting the workpiece, the improvementcomprising: key and the trailing finger then abuts the key, whereafter awork driver which includes: the key is snugly engaged therebetween,whereby the a floating driving block having opposed work engagingsurcamshaft is oriented in a predetermined angular position faces, withrespect to said driving head.

means for hingedly mounting said work driver so that the 4. In anautomatic grinding machine for grinding axially work engaging surfacesadjust to variances in the spaced cam lobes of an automotive camshaft,the camshaft periphery of the workpiece, having a projecting indexingelement or key, the machine insaid floating driving block furtherincluding indexing means cluding a base, a grinding wheel support onsaid base, a grindfor enabling a workpiece to be automatically loaded ina ing wheel rotatably mounted on said wheel support, a work randomangularly oriented position, support comprising a carriage slidablymounted on said base, a said indexing means also forming one drivingsurface rocking work cradle pivotably mounted to said carriage, a

against said key and one of said work driver surfaces headstock and atailstock on said cradle for rotatably supportforming another drivingsurfaces against the workpiece ing a camshaft, a master cam on saidheadstock having cam P p y to Provide a mechanical p contours for eachcam lobe on the camshaft, a master cam folan automatic work loader fortransferring unground worklower, a pair of work rests which are securedto said cradle to pieces to said work rest; support two spaced bearingdiameters on the camshaft, the means for shiftingthe work center of thetailstock longituimprovement comprising:

dinally to move the workpiece axially into driving'engagea work driverwhich includes, ment with said work driver and said headstock work afloating driving block having opposed work engaging surcenter; andfaces, means for restraining rotation of said workpiece and simulmeansfor hingedly mounting said work driver so that the taneously slowlyrotating the work driver to orient the work engaging surfaces adjust tovariances in the workpiece in said indexing means relative to aheadstock. 4O periphery of the workpiece,

2. in an automatic grinding machine for grinding axially said floatingdriving block further including indexing means spaced cam lobes of anautomotive camshaft, the camshaft for enabling a camshaft to beautomatically loaded in a having a projecting indexing element or key,the machine inrandom angularly oriented position, eluding a base, agrinding wheel support on said base, a grindsaid indexing means alsoforming one driving surface ing wheel rotatably mounted on said wheelsupport, a work against said key and one of said work driver surfacessupport comprising a carriage slidably mounted on said base, a forminganother driving surface against the camshaft rocking work cradlepivotably mounted to said carriage, a periphery to provide a mechanicalcouple; headstock and a tailstock on said cradle for rotatably supportanautomatic work loader for transferring unground ing a workpiece, amaster cam on said headstock having cam camshafts to said work rests;contours for each carn lobe on the camshaft, a master cam folmeans forshifting the work center of the tailstock longitulower, a pair of workrests which are secured to said cradle to dinally to move the camshaftaxially into driving engagesupport two spaced bearing diameters of thecamshaft, the imment with said work driver and said headstock workprovement comprising: center; and

an automatic work loader for transferring unground means for restrainingrotation of said camshaft and simulcamshafts to said work rests;taneously slowly rotating the work driver to orient the work drivermeans for receiving a camshaft in a random ancamshaft in said indexingmeans relative to said master gularly oriented position from the workloader; cam.

said work driver including indexing means for engaging and 5. A workholding device for transmitting a torque to a driving the camshaft bysaid key; workpiece having a projection or key which comprises:

means for shifting the work center of the tailstock longitua drivinghead having a pair of spaced protruding pins exdinally to move thecamshaft axially into driving engagetending therefrom;

ment with said work driver and said headstock work a link pivotallymounted on each of said pins,

center; and said links extending in generally parallel directions, andmeans for restraining rotation of said camshafi and simulhaving studsextending from the free end thereof;

taneously slowly rotating the work driver to orient the key a floatingmember secured between said studs for limited in said indexing meansrelative tosaid master cam. radial movement about said pins;

3. An automatic grinding machine as recited in claim 2, afingerpivotally mounted on each of said studs, wherein said work drivercomprises: the ends of said fingers being held apart a distance subadriving head having a pair of spaced protruding pins exstantially equalto the width of the projection when the tending therefrom; fingers areco-axially aligned toward each other about a link pivotally mounted oneach of said pins, the studs by said floating member;

said links extending in generally parallel directions, and means forresiliently urging said fingers into co-axial alignhaving studsextending from the free end thereof; ment to engage the workpieceprojection on two sides;

a floating member secured between said studs for limited means on saidfloating member for engaging opposite sides radial movement about saidpins; of the workpiece to position the floating member concen- 8 afinger pivotally mounted on each of said studs,

the ends of said fingers being held apart a distance substantially equalto the width of the key when the fingers are co-axially aligned towardeach other about the from the workpiece projection and the trailingfinger then abuts the projection, whereafter the projection is snuglyengaged therebetween, whereby the workpiece is oriented in apredetermined angular position with respect to said driving head.

1. In a machine tool for removing material from a workpiece, theworkpiece having a projecting indexing element or key, the machineincluding a tool, a headstock and a tailstock for rotatably supportingthe workpiece, at least one work rest for supporting the workpiece, theimprovement comprising: a work driver which includes: a floating drivingblock having opposed work engaging surfaces, means for hingedly mountingsaid work driver so that the work engaging surfaces adjust to variancesin the periphery of the workpiece, said floating driving block furtherincluding indexing means for enabling a workpiece to be automaticallyloaded in a random angularly oriented position, said indexing means alsoforming one driving surface against said key and one of said work driversurfaces forming another driving surfaces against the workpieceperiphery to provide a mechanical couple; an automatic work loader fortransferring unground workpieces to said work rest; means for shiftingthe work center of the tailstock longitudinally to move the workpieceaxially into driving eNgagement with said work driver and said headstockwork center; and means for restraining rotation of said workpiece andsimultaneously slowly rotating the work driver to orient the workpiecein said indexing means relative to a headstock.
 2. In an automaticgrinding machine for grinding axially spaced cam lobes of an automotivecamshaft, the camshaft having a projecting indexing element or key, themachine including a base, a grinding wheel support on said base, agrinding wheel rotatably mounted on said wheel support, a work supportcomprising a carriage slidably mounted on said base, a rocking workcradle pivotably mounted to said carriage, a headstock and a tailstockon said cradle for rotatably supporting a workpiece, a master cam onsaid headstock having cam contours for each cam lobe on the camshaft, amaster cam follower, a pair of work rests which are secured to saidcradle to support two spaced bearing diameters of the camshaft, theimprovement comprising: an automatic work loader for transferringunground camshafts to said work rests; work driver means for receiving acamshaft in a random angularly oriented position from the work loader;said work driver including indexing means for engaging and driving thecamshaft by said key; means for shifting the work center of thetailstock longitudinally to move the camshaft axially into drivingengagement with said work driver and said headstock work center; andmeans for restraining rotation of said camshaft and simultaneouslyslowly rotating the work driver to orient the key in said indexing meansrelative to said master cam.
 3. An automatic grinding machine as recitedin claim 2, wherein said work driver comprises: a driving head having apair of spaced protruding pins extending therefrom; a link pivotallymounted on each of said pins, said links extending in generally paralleldirections, and having studs extending from the free end thereof; afloating member secured between said studs for limited radial movementabout said pins; a finger pivotally mounted on each of said studs, theends of said fingers being held apart a distance substantially equal tothe width of the key when the fingers are co-axially aligned toward eachother about the studs by said floating member; means for resilientlyurging said fingers into co-axial alignment to engage the key on twosides; and means on said floating member for engaging opposite sides ofthe camshaft to position the floating member concentrically with theperiphery of the camshaft, one of said fingers and one of said engagingmeans forming spaced force applying surfaces to provide a mechanicalcouple to the camshaft, so that when the camshaft is restrained againstrotation and said driving head is slowly rotated, the fingers willrotate until the leading finger engages and pivots away from the key andthe trailing finger then abuts the key, whereafter the key is snuglyengaged therebetween, whereby the camshaft is oriented in apredetermined angular position with respect to said driving head.
 4. Inan automatic grinding machine for grinding axially spaced cam lobes ofan automotive camshaft, the camshaft having a projecting indexingelement or key, the machine including a base, a grinding wheel supporton said base, a grinding wheel rotatably mounted on said wheel support,a work support comprising a carriage slidably mounted on said base, arocking work cradle pivotably mounted to said carriage, a headstock anda tailstock on said cradle for rotatably supporting a camshaft, a mastercam on said headstock having cam contours for each cam lobe on thecamshaft, a master cam follower, a pair of work rests which are securedto said cradle to support two spaced bearing diameters on the camshaft,the improvement comprising: a work driver which includes, a floatingdriving block having opposed work engaging surfaces, means for hingedlymounting said work driver so that the work engaginG surfaces adjust tovariances in the periphery of the workpiece, said floating driving blockfurther including indexing means for enabling a camshaft to beautomatically loaded in a random angularly oriented position, saidindexing means also forming one driving surface against said key and oneof said work driver surfaces forming another driving surface against thecamshaft periphery to provide a mechanical couple; an automatic workloader for transferring unground camshafts to said work rests; means forshifting the work center of the tailstock longitudinally to move thecamshaft axially into driving engagement with said work driver and saidheadstock work center; and means for restraining rotation of saidcamshaft and simultaneously slowly rotating the work driver to orientthe camshaft in said indexing means relative to said master cam.
 5. Awork holding device for transmitting a torque to a workpiece having aprojection or key which comprises: a driving head having a pair ofspaced protruding pins extending therefrom; a link pivotally mounted oneach of said pins, said links extending in generally paralleldirections, and having studs extending from the free end thereof; afloating member secured between said studs for limited radial movementabout said pins; a finger pivotally mounted on each of said studs, theends of said fingers being held apart a distance substantially equal tothe width of the projection when the fingers are co-axially alignedtoward each other about the studs by said floating member; means forresiliently urging said fingers into co-axial alignment to engage theworkpiece projection on two sides; means on said floating member forengaging opposite sides of the workpiece to position the floating memberconcentrically with the periphery of the workpiece, one of said fingersand one of said engaging means forming spaced force applying surfaces toprovide a mechanical couple to the workpiece, so that when the workpieceis restrained against rotation and said driving head is slowly rotated,the fingers will rotate until the leading finger engages and pivots awayfrom the workpiece projection and the trailing finger then abuts theprojection, whereafter the projection is snugly engaged therebetween,whereby the workpiece is oriented in a predetermined angular positionwith respect to said driving head.